Problem: Expand.
Explanation: $\begin{aligned} &\phantom{=}({-8a^2-1})(3a^2-5) \\\\ &={-8a^2}(3a^2-5){-1}(3a^2-5) \end{aligned}$ $\begin{aligned} &=-24a^4+40a^2-3a^2+5 \\\\ &=-24a^4+37a^2+5 \end{aligned}$